EDEN PRAIRIE, Minn.—The frustration mounts for Vikings defensive end Jared Allen, the reigning NFL sack king who has now gone three games without a sack for only the fifth time in his nine-year career.

Yes, he had seven sacks in six consecutive games before his current drought. Yes, he had seven total sacks during that six-game stretch. But anytime Allen faces the Chicago Bears’ woeful pass protection and doesn’t come away with a sack, that’s the height of frustration for him.

In last year’s season finale, Allen went into the Bears game with 18½ sacks. He needed 3½ sacks to break the team record set by Hall of Famer Chris Doleman and four sacks to break the NFL mark set by Michael Strahan. Allen was unstoppable, notching 3½ sacks with Doleman looking on as his team mark fell. Allen finished the season with 22 sacks, tying him with Mark Gastineau for the second most in NFL history.

Granted, that game was at the Metrodome and Allen’s only focus was on rushing the passer since the Vikings were 3-12 at the time. But Allen should have been able to get to Jay Cutler at least once during last Sunday’s game at Soldier Field.

Vikings coach Leslie Frazier isn’t voicing concern. He says Allen still is affecting games because teams devote extra protection schemes to his side. He also noted that the Bears went away from their deep passing routes to more quick-hitting underneath stuff because of Allen’s presence.

It also hurt the Vikings that the Bears’ offensive line was humiliated the previous Monday night while giving up six sacks, including 5½ to Aldon Smith, in a 32-7 loss at San Francisco. The Bears benched two linemen and lost two more to injury during the Vikings game, yet the only sack they suffered came when Cutler tripped over his center’s foot and fell on Chicago’s first play from scrimmage.

Besides not being sacked, Cutler also wasn’t harassed much throughout the game. Even with all the excuses to suggest it wasn’t a concern, Allen’s low profile against the Bears raises a red flag heading to Green Bay, where the Vikings face another suspect pass-protection team on Sunday.

If the Packers hold Allen without a sack, it will be only the second time he’s ever gone four games without one. The only other time came during the 2010 season.